Patients with nephrotic syndrome often have abnormalities in lipid metabolism. These may arise from increased synthesis of lipoproteins by the liver. This study is designed to test the effect of a dietary adjustment using fish oil versus olive oil (isocaloric diets) to examine the effect of dietary lipid composition on the synthesis of VLDL using a stable isotope, N15-luecine, as a tracer of VLDL kinetics and metabolism in subjects with nephrotic syndrome who consume a fish oil or olive oil enhanced diet for 6 weeks intervals.